Power hacksaw-machine.



A. RASMUSSEN.

POWER HACKSAW MACHINE.

APPLICATION FILED ma. :4, 1916.

2 $HEETSSHEET I.

Patented Jan. 9

A. RASMUSSEN.

POWER HACKSAW MACHINE.

APPLICATION nun ru. n. 4915.

Patented Jan. 9,1917.

2 SHEETS*SHEET 2.

ANDREW BABMUSSEN, 0F RACINE, WISCONSIN.

rowan HAOKSAW-MAGHINE.

Specification of Letters Patent.

Patented Jan. 9, 1917.

Application filed February 14, 1916. Serial No. 78,148.

To all whom it may concern Be it known that 1, ANDREW Rasmussen, a citizen of the United States, and a resident of Racine, in the county of Racine and State of Wisconsin, have invented certain new and useful Improvements in Power Hacksaw-Machines; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accom anying drawings, and to the characters oi reference marked thereon, which form a part of this specification.

This invention relates to improvements in hack saws, and refers more particularly to an improvedmeans to feed the saw blade toward the work during the cutting stroke thereof and to release it from the work during the non-cutting stroke so as to thereby avoid wear thereof and to facilitate the cooling of the saw blade during the non-cutting stroke.

M improvements are herein shown as a plie to the type of hacksaw illustrated in my prior U. S. Patent No. 1025305, dated May 7th, 1912, wherein the feeding means comprises means independent of the Weight of the reciprocating saw frame and its guide for depressing the saw to its work during the cutting stroke.

Among the objects of the present invention are to increase the eificiency of saws of this character by a mechanism which delicately controls the cutting and the non-cutting stroke of the saw so as to avoid an un-' duly heavy pressure of the saw against its Work during its cutting stroke, and to avoid too great a rise of the saw blade from the work during the non-cutting stroke, so that without any tendency to break the same when the saw is pressed to the work in the subsequent cutting stroke.

A further object of the invention is'to provide, in a sawing machine of this general character, means for raising the saw at the end of its cutting'stroke, combined with means for limitingthe rising movement of said saw so that upon the next succeeding cutting stroke the saw is required to be de pressed but a short distance to its work, thereb avoiding abrupt contact of the saw with t e work.

Another object of the invention is to pro vide means for preventing sudden descent of the saw frame and its guide in the event of the breaka e of a saw blade tending to break the guid e and frame or other parts of the machine.

Other objects of the invention are to improve and simplify hack saw feed mechanisms, and the invention consists in the combination and arrangement of the parts shown in the drawings and described in the specification and is pointed out in the appended claims.

In the drawings, Figure 1 is a side elevation, with parts shown in section, of a hack saw embodying my improvements. Fig. 2 is a top plan view thereof. Fig. 3 is a vertical section on the line 3-3 of Fig. 1. Fig. 4 is a partial side elevation of a power hack saw, on a smaller scale, showing a modification of the feed means.

A hack saw machine embodying my improvements, so far as its general features of construction are concerned, may follow any preferred type of design. For sake of clearness of the essence of the present invention the elements of the saw structure, aside from the invention, are of a simple construction and design. The frame of the saw consists of a horizontal table 10 having suitably 10 cated openings therein for the passa e of operative parts of the machine and which is supported on legs, 11, 11.

12 designates a vertically swinging saw frame guide and support that is pivotally mounted at its rear end on the main drive shaft 13 of the machine and supports at its forward end the usual sliding saw frame 14,

between the legs of which is stretched a hack saw blade 15. i in the subsequent cutting stroke the saw blade will be pressed gently to the work,and

The recipaaaiingfsaw frame 14 is connected by u pitman 16 to a suitable crank actuated by the shaft 13, consisting in this instanm of an eccentrically disposed crank pin 17 of a crank disk 18 that is fixed to said shaft 13. Said shaft 13 is mounted in separate bearings 20, 20, which rise from the rear end of the table 10, and the shaft is rovided at one end with a belt pulley 21.

he weight of the saw frame and guide will be overbalanced around it pivot 13 so as to tend to raise the saw rune and saw when no feed pressure is merted thereon, either by means of a. weight or sprin As herein shown said overbalancing e eat is produced by a spring 25 which surrounds a rod 26 that is loosely connected at one end to a tail piece 27 of the guide 12 and is provided at its other end with a shoulder 28, between which and a downwardly facing surface on the frame 10 said spring is interposed. Said shoulder 28 constitutes part of, or is associated with an adjusting not which is screw threaded to the rod, whereby the overbalaneing pressure of the spring 25 may be delicately adjusted. Obviously a weight suitably applied to the tail piece 27, in the same general manner as shown in my aforesaid prior patent, may effect the same general result, but the spring is preferable, pccially in the larger sizes of sawing ma.- chines.

The W is fed toward its work during the cutting stroke thereof, to wit, the rearward stroke of the frame 14. by feed means gen erally like that shown in my aforesaid prior U. S. l ietters Patent, said feed means enrbracing a ratchet connected to the frame and a l'ced dog which is controlled by movement derived from the power shaft 13 and acting during the utting stroke of the saw to draw the saw supporting framedownwardly. The specifi form ol'dm-chanism shown in Figs. 1, L and ii, embraces in general terms, a hollo\ ratchet bar 30 which is slidable on. a T-shaped guide 31 which is attached by a bra ket 3:5 to the machine frame. Said ratchet bar is connected by a link 33 to the saw guiding frame 12, the link 33 being herein shown. as loosely connected at its lower end by a pin ill. to the lower end oi the ratchet bar and at its upper end by a bolt or pin 35 to an arm so which is fixed to and depends from said saw frame sup porting guide. (loiiperatingwith the ratchet bar It is a feed dog which is provided with teeth to engage the teeth of the ratchet bar. Said feed dog, which is of general L-shape as herein shown, is pivoted at 41 to the forward end of a lever l2, which lat tcr pivoted t, 42K to a standard 4-4 that rises from the lsase or bed plate 10 of the machine. The dog 10 may be Weighted so as normally to be pressed toward the ratchet bar 30. Preferably, however, a light spring 45 is applied to said dog for this purpose which is attached at one end to a bracket 46 depending from the bed plate, and at its other end to an arm 47 which extends downwardly and rearwardly from the feed dog. The rear end of the lever 42 carries a bear ing roller 48 which engagesthe periphery of a cam 49 that is fixed to and rotates with the shaft 13, or may be otherwise suitably driven therefrom. The periphery of the cam 49 is divided into two equal parts, towit, a higher part a and a lower part 1), Connected by oblique or cam portions 0", all as shownin dotted lines in Fig. 1.

The bearing roller 48 carried by the rear end of the lever 42 is normally pressed toward or against the periphery of the Cam 49 by means permittin" said latter end of the lever to yield backuuu'dly away from the axis of the cam. This may be eli'ected either through the action of a spring or a weight; spring 50 being herein employed as in my aforesaid prior construction. The spring 50 which, in the illustrated embodiment is spiral, surrounds a shaft or rod 51 that is loosely connected at Tr. to the rear end of the lever on the axis of the roller J8; said spring being interposed between a shoulder 53 on said rod or shaft 51 and one arm 54. of an L-shaped love 55 that is perforated for the passage of the rod 51. Said rod 51 is screw threaded at its lower end below said. arm 54? to receive a not or nuts 56 to prevent d tachment of the rod from said lever. The lever 55 is pivoted at 57 to the machine frame and is shown as made in tegral with or fixed to an adjusting lever 59 that extends forwardly from the pivot 117 and is provided with a suitable latch 60 whi h coiipeiatcs with a segmental locking bar 1 fixed to the forward end of the machine.

The lever 58 and its spring connection with the dog carrying lever 42 constitute means for varying the pressure of the saw against the work. \Vhen sawing relatively soft metals the spring 50 may be adjusted so as to press the bearing roller 48 of said lever 42 into contact with the lower portion 6" of the cam it) so as to obtain the maximum cut of the saw. The contact of the roller with this portion of the cam limits the feed movement of the lever in each operation of the saw. When cutting harder metals the spring MI will be adjusted to press the saw lightly against the workv It will be understood that when the bearing roller is engaged with the higher track of the cam the for 'ard end of the lever 42 is raised so as to release the feed dog from its ratchet bar and permit the saw frame to be raised under the action of the spring 2-. I

Operating in connection with the feed dog 40 a stop or check dog 60 which limits the upward swing of the saw frame and guide between the cutting and non-cuttin stroke. Said dog is pivoted to a fixed stud 61 on the machine frame below the feed dog and is adapted to be normally held with its teeth engaging with the teeth of the ratchet bar 30 either by gravity or by a, spring 62, the latter being preferred. paid spring is connected between the lug 46 and a tail piece 63 on the stop dog. The function of the stop dog is to limit the rising movement of the saw frame during the non-cutting stroke of the saw and at a time when the feed dog is released from the feed ratchet bar so that when said feed dog is again depressed through its feedstroke the teeth thereof engage with teeth of the ratchet bar above those engaged in the earlier feed movements of the dog with the result of positively and progressively feeding the saw to the work during each cutting stroke thereof.

lVhen cutting hard material the feed dog may not be raised at each release thereof from the ratchet to carry it into engagement -with the next higher ratchet tooth, but may operate through two or more feed strokes on one ratchet tooth. However, the stop or check dog prevents the rising of the supporting guide under the action of its spring to such height to cause the ratchet tooth last engaged to pass beyond the dog, such as would occur if the stop dog were not present, so that the feed action on the ratchet bar is a progressive and a positive one. The

said check dog is hinged to the machine frame by means reventing lost motion. This may be effected by elongating the aperture therein through which the stud 61 extends. Such lost motion mounting of the stop dog allows slight upward movement of the dog and bar after the stop dog engages the ratchet bar and thereby prevents the latter dog from locking the ratchet bar against upward movement in the event that the lock dog should. engage the ratchet teeth in a position favorable for positive locking, as when the abrupt faces of the teeth of the stop dog and ratchet bar were in contact at the time of the release of the feed dog. It will be understood that the rise of the saw, blade in the saw cut need not be great, only sufiicient to allow complete clearance of the saw blade teeth from the bottom of the saw cut. I ha \e found in practice that sixteen pitch teeth on the ratchet bar are suflicicnt to produce the desired clearance. if desired the feed and stop dogs may be double, with one member offset from the other as indicated in Fig. 3.

Both the feed and locking dogs may be released from the ratchet bar to permit the saw frame to be raised at the end of a cut by means of an arm 65 carried by a rock shaft 66 which is mounted in suitable bearings carried by the bed plate. Said shaft is provided at one side of the machine with a throw-out lever (38. The arm 65 islocated in a position to simultaneously enga e both the tall pieces 497 and 62 of said fee and locking dogs, resl'iectively. \Vhen the dogs are released the spring 25 raises the saw frame a distance to permit new work to be clamped in the machine for the next cut. The dis tance which the saw frame is thus raised at b c e: of each cutting operation is preferably l. uitcd to the extent only required by the clearance beneath the saw blade to adjust the work in the holding jaws. A practical form of limiting stop herein shown consists of a bar 70 which is loosely connected at its lower end at 71 to the bed plate and extends upwardly through an apertured enlargement 72 of the swinging supporting guide or frame 12. The said bar is provided at its upper end with a stop collar 73 which is slidable thereon and is adapted to be. locked thereto in difl'erent positions of vertical adjustment by a thumb screw 74, and engagement of which by the supporting guide limits the upward movement of the saw.

In Fig. 4 I have shown an endless or disk form of feed rack which cooperates with the feed and stop dogs to control the feed movement of the saw. The said disk designated by is mounted to rotate on a shaft 81 which is carried by depending brackets 82 of the machine frame. Rotating with said ratchet Wheel and fixed thereto, as herein shown, is a drum 83 on which is adapted to be wound a cable 84, that is attached to the saw frame supporting guide 12. A feed dog 85 engages said ratchet disk, said feed dog being formed on the lower end of a bar 87 which is loosel connected or hinged at 88 to the forward end of the cam controlled feed lever 89. The said dog 85 is shown as normally held against the endless ratchet by a spring 90 connected at one end to the dog and at its other end to one of the brackets 8.2. In the present instance the stop dog 92 engages the side of the disk remote from the feed dog. Said stop dog is pivoted to a. bracket93 which is attached to and depends from the machine frame and is placed under the action of a spring 94 which is attached at one end to the tail piece of the dog and is attached at its other end to a fixed part 95 which is attached to and depends from the machine frame. The operation of this form of feed device is generally the same as in the construction heretofore described and said feed disk and feed dog are generally like the feed disk and d0 shown in my aforesaid prior patent. I lave not shown means for simultaneously releasing feed dog and check dog from the disk, but this may be effected in a manner to that similarly illustrated in Fig. 1.

It will be observed that in the event of a breakage of the saw blade, the overbalancing effect of the spring 25 or equivalent means will have the effect to at once raise the forward end of the saw supporting guide, and thereby prevent the guide from dropping downwardly on the bed with such force as would tend to break the same. In certain prior constructions of back saws it has been common to utilize the weight of the 'saw frame and its guide, and in some constructions, an additional weight carried by the saw frame. In such prior constructions the full force of this feed weight is carried by the saw blade and, in case of breakage of the blade, said weighted parts, being nonsupported, drop abruptly on the bed with theresult that the guide is often broken. It will also be observed that the use of the adj ustable device, consisting in this instance of the spring 25 in connection with the loi king dog 60, has the effect to delicately baiance the saw so that while the saw is lifted clear of the bottom of the saw cut during this noncutting stroke, the extent of the lift is small. As a result thereof the saw blade is pressed gently against the work in the beginning of the cutting stroke, thei'eby avoiding such abrupt contact of the saw with the work as would tend to break the saw.

It will be understood that the illustrated embodiment of my invention is capable of some variations within the spirit and scope of the chi as hereto appended, and it is the intent to claim all of the inherent novelty shown in the drawings and described in the specification.

I claim as my invention 1. Feeding means for power hack saw machines comprising, in combination. a reciprocating saw frame, a vertically movable supporting guide thercfor, moans acting on the guide to overbalance the saw frame to lift the saw from the work during the noncutting stroke, means acting in opposition to the mcrlmlancing means to feed the saw to its work during the cutting stroke and means for limiting the lifting movement of the saw.

2. Feeding means for power hack saw machines comprising, in combination, a reciprocating saw frame, a vertically movable supporting guide therefor, means acting on the guide to overhalance the saw frame to lift the saw from its work during the noncutting stroke, a cam controlled lover, a' feed dog carried by the lever, a ratchet member operatively associated with said supporting guide, for operative engagement by the dog and a check device for limiting the lifting movement of the saw.

3. Feeding means for power hack saw ma chines con'iprising, in combination, a reciproeating saw frame, a vertically swingable supporting guide therefor. means acting on i the guide to overbalance the weight of the saw frame and the for uird end of theguidc to lift the saw from its work, a ratchet mem ber operatively associated with the saw supporting guide, a cam controlled lever, a feed dog mounted on. the lever to engage the ratchet member (luring the cutting stroke of the saw to press the saw toward its work and adapted to be released from the ratchet member during the non-cutting stroke of the saw, and a locking dog to engage the ratchet when the feed do" is releascd to limit the rising movement of t w supporting guide under the action of said over-balancing means.

4. Feeding means for power back saw machines comprising, in combination, a recip- Locating frame, a vertically movable supporting guide therefor, means acting on the lift the saw from its work, a ratchet member iopcratively associated with the saw supporting guide, a. cam ontrolled lever, a feed do mounted on the ever to engage the ratchet member during the cutting stroke of the saw to press the saw toward its work and adapted to be released from the ratchet member during the non-cutting stroke of the saw, a locking dog to engage the ratchet member when the feed dog is released to limitthe rising movement of the supporting guide under the action of said overbalancing means, and a throw-out device having means to simultaneously act upon both dogs to release them from said ratchet member.

5. Feeding means for power hack saw machines comprising, in combination, a reciprocating saw frame, a vertically movable supporting guide therefor, means acting on the guide to overbalance the wei ht of the saw frame and the forward end 0 the guide to lift the saw from its work, a. ratchet member opcratively associated with the saw supporting guide, a cam controlled lever, a feed dog mounted on the lever to engage the ratchet member during the cutting stroke of the saw to press the saw toward its work and adapted to be released from the ratchet in the non-cutting stroke of the saw, a locking dog to engage the ratchet member when the feed dog is released to limit the rising movement of the supporting guide under the action of said overbalancing means and a rock shaft mounted in the machine and provided with a throw-out arm to engage said dogs, with means to rock said shaft.

6. Feeding means for power hack sawinachines comprising, in combination, a reciprocating saw frame, a vertically movable supporting guide therefor, means actin on the guide to ovcrbalance the Weight 0 the saw frame and the forward end of the guide to lift the saw from its work, means acting in opposition to said ovcrbalancing means to positively feed the saw to its work during its cutting stroke and to be released from the saw during its non-cutting stroke, locking means to limit the rising movement of the saw during its non-cutting stroke, and means to limit the rising'movcment of the supporting guide when the feeding means and locking means are released from the SHAV- 7. A power hack saw machine comprising, in combination, a saw frame, its vertically movable supporting guide, a power shaft on which said guide 15 pivoted, a controlling cam mounted on said shaft, operative connection between the said shaft and saw frame for reciprocating the latter, a lever pivoted between its ends to the machine and carrying at one end a hearing member to engage the periphery of said cam, means tending to urge the bearing roller toward the cam, a ratchet member operatively associated with the supporting guide, a feed dog carried by the other end of said lever and co operating with the ratchet member to feed the saw to its work, means acting on the supporting guide to overbalance the weight of the saw frame and the forward end of the guide when the feed do is released and means coiiperating with said ratchet member for limiting the upward movement of the guide and saw frame when the feed dog is so released.

8. A power hack saw machine comprising a. power shaft, a reciprocating saw frame, a supporting guide for the frame pivoted to said shaft, overbalancing means acting on said guide to lift the saw from its work, operative connections between said shaft and saw frame to reciprocate the latter, a cam on said shaft, a lever pivoted between its ends to the machine frame, and carrying at its forward end a feed dog, a ratchet member operatively associated with said supporting guide and coiiperating with the feed dog to feed the saw to its work against the action of said over-balancing means, a bearing member carried by the rear end of said lever for engagement with said cam, means tending to urge said bearing member toward the cam, said cam beingshaped to permit the feed means to act on the rear end of the lever and depress the dog during the cutting stroke of the saw, and to release the feed dog from the ratchet member during the non-cutting stroke of the saw.

9. Feeding means for power hack saw machines, comprising in combination, a frame normally overbalanced away from the work,

and feeding means comprising a ratchet member associated with the saw frame, a

A feed dog cotiperating with the ratchet memher to feed the saw toward the work and a. stop dog also cooperating with the ratchet to limit the movement of the saw away from the work.

10. Feeding means for power hack saw machines, comprising in combination, a frame normally overbalanced away from the work, and feeding means comprising an endless ratchet, a drum associated therewith, a cable connecting the drum to the saw frame, a feed dog operatively engaging the ratchet to feed the saw to its work, and a stop dog cooperating with the ratchet to hold the saw frame from rising when the feed dog is released.

11. A power hack saw machine comprising a swinging saw frame and its guide, a shaft on which said guide is pivoted, said guide provided with a tail piece extension, a spring applied to the tail piece extension to overbalance the saw frame and guide away from the work, a cam-controllwl, yieldingly actuated fegd device for feeding the saw to its Work, and a check dog to limit the raising of the saw frame when the feed device is released.

12. A power hack saw machine comprising a. swinging saw frame and its guide, a shaft on which said guide is pivoted, said guide provided with a tail piece extension, a spring applied to the tail piece extension to overbalance the saw frame and guide away from the work, adjusting means to vary the overbalancing force of said spring, a cam-controlled, yieldingly actuated feed device for feeding the sawto its'work, and a check dog to limit the raising of the saw frame when the feed device is released.

13. A power hack saw machine comprisin a swinging saw frame and its guide, a shaft on which said guide is pivoted, said guide provided with a tail piece extension, over: balancing means for the saw frame and guide acting on said tail piece extension, a ratchet member associated with said guide, a feed dog coo eratin therewith to feed the same toward tlie wor a cam controlled lever carrying said dog, a spring actin on said lever to move the feed dog throng its feed stroke and a check dog acting on said ratchet member to limit the movement of the saw away from the work.

14. A power hack saw machine comprisin a swinging saw frame and its guide, a she I; on which said guide is pivoted, said guide provided with a tail piece extension, over alancing means for the saw frame and guide acting on said tail piece extension,,a ratchet member associated with said guide, a feed dog e06 eratin therewith to feed the same toward t e wor a cam controlled lever carrying said dog, a spring acting on said lever to move the feed dog through its feed stroke, a check dog acting on said ratchet member to limit the retiring move ment of the saw and adjusting means tovary the force of the feed dog actuating spring.

15. A power hack saw machine comprisin a shaft, a swingin saw frame guide pivoted to the shaft and ormed with a rearwardly extending tail piece, a rod connected to the tail piece, a spring surrounding the rod and interposed between an abutment on the machine frame and a shoulder on the lower end of the rod, means acting on the saw frame guide in opposition to the overbalancing action of said spring to feed the saw to the Work, and check means acting to limit the rising of said guide when the feed means i released. a

16. A power hack saw comprisinga swinging saw frame guide normally overbalanced away from the work, a shaft on which the guide is pivoted, a ratchet member associated with said guide, a controlling cam, a lever pivoted between its ends and hearing at one end against the controlling cam, a feed dog carried by the other end of said lever, a

springacting on the bearing end of said lever to press it toward said cam and to thereby swing the feed dog through a feed stroke, and a check dog cooperating with said ratchet member to limit the movement of the saw away from its Work.

17. A power hack saw comprising a swinging saw frame guide normally over-balanced may from the work, a shaft on which the guide is pivoted, a ratchet member associated with said guide, a controlling can], a lever pivoted between its ends and bearing at one end against the controlling cam, a feed dog carried by the other end of said lever, a spring acting on the bearing end of said lever to press it toward said cam and to thereby swing the feed dog through a. feed stroke, a. check dog cooperating with said ratchet member to limit the movement of the saw away from its work, and adjusting means to vary the force of the spring.

18. Apower hack saw comprising a swing ing saw frame guide normally orerbalanced away from the work, a shaft on which the guide is pivoted, a ratchet member associated with said guide, a controllin cam, a lever pivoted between its ends and iearin at one end against the controlling cam, a eed dog carried by the other end of said lever, a rod connected with the bearing end of said lover, a spring surrounding the rod and hearing at one end against a shoulder on the rod, an adjusting lever perforated for the passage of said rod therethrough and bearin g against the other end of said spring, with means to lock the adjusting lever in adjusted posr tions and a. check dog cooperating with said ratchet member to limit the movement of the saw away from its work.

In testimony that I claim the foregoing as my invention I afi'ix my signature in the presence of two witnesses, this 1st day of February, A. D. 1916.

ANDREW RASMUSSEN.

Witnesses:

W'. L. HALL, IRENE Fonnnsr. 

